Device for gauging and adjusting springs



C. B. EMERY DEVICE] FOR GAUGING AND ADJUSTING SPRINGS Jan. 18, 1927.f1,615,117

Filed Oct. 1923 45 47 v u {QM C fi 2 v 5 36 1 if Inventorclzczfldfli'mely Patented Jan. 18, 1927.

UNITED STATES PATENT OFFICE.

CHARLES BREVET EMERY, 0F RIVER FOREST, ILLINOIS, ASSIGNOR TO WESTERNELEC- TBIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OFNEW YORK.

Application filed. October 8, 1923. Serial No. 667,150.

This invention relates to devices for gauging and adjusting springs, andmore particularly to devices for gauging and adjusting the contactpressure of electrical contact springs.

An object of the invention is the provision of a device for gauging andadjusting the contact pressure of contact springs such as are used onmulti-contact brushes of telephone exchange apparatus of the machineswitching type.

Another object of the invention is to provide a device of'the abovementioned type, which comprises a leaf spring adapted to be adjusted toprovide different resilient values.

A further object of the invention is to provide a device combining meansclosely associated upon a common support for rapidly gauging andadjusting the contact pressure of a plurality of closely spaced contactsprings.

In telephone exchange apparatus of the machine switching type, themechanism is compactly arranged to conserve space and includesmulti-contact brushes, each mounting a plurality of contact springswhich are moved over a plurality of contact surfaces in the operation ofthe mechanism. In mechanism of this type it is essential that thecontact pressure of each spring should be sufiicient to insure propercontact with the contact surface over which it moves Without causing anundue wear thereon or consumption of power in moving the same.

A device made in accordance with theinvention may comprise a support orhand grip having adjustably mounted thereona leaf spring having aresiliency equal 1n value to the desired contact pressure of the springsto be gauged and adjusted. The free end of the leaf spring is equippedwith a plurality of engaging portions for successively and selectivelyengaging a plurality of closely spaced springs mounted in the sameplane. The support or hand grip is provided with a plurality of recessesforming fixed jaws for engaging the springs to adjust them when found toexert a force which is more or less than the desired contact pressure.

These and other features of the invention not specifically mentionedwill clearly appear from the following description and the accompanyingdrawings, in wh1ch'- Fig. 1 is a fragmentary plan view of the devicemounted in one of its adjusting positions upon one of the contactsprings of a multi-contact brush which is shown positioned on thecommutator of a machine switching telephone exchange system;

Fig. 2 is a fragmentary side View of the brush member and the commutatorwith the device shown in several of its adjusting positions;

Fig. 3 is a section taken on the line 3-3 of Fig. 2 with the deviceshown in several different gauging and adjusting positions;

Fig. 41 is a fragmentary side view of the device shown engaged with aspring under test, and

Fig. 5 is a fragmentary plan view of the device.

Referring to the drawings in detail, in which similar referencecharacters are employed to denote similar parts throughout the variousviews, 10 indicates a commutator of a type frequently employed intelephone exchange apparatus of the machine switching type. Amulti-contact brush 11 attached to a brush rod 12 by means of a clampingdevice 13 is adapted, in the opera tion of the telephone exchangesystem, to move resilient spring contact members 14:, 14 over thecommutator 10, which may consist of metal contacting strips, such as 24,24, embedded in a block of insulating material 28. Although in the useof such a commu tator and the associated apparatus the brush andsupporting rod are mounted upon a suitable frame work and the contactsurfaces may be suitably connected to the operating circuits of theexchange, such features are not essential to a complete understanding ofthe invention and have therefore been omitted from the drawings.

In the preferred embodiment of the invention which is devised forgauging and adjusting the contact pressure or resiliency of the springs141, 1 1, a metal bar 30, square in cross section'is bent substantiallymidway along its length, as shown, to form a hand grip 31 forconveniently holding the tool in position in the hand without danger ofit turning in the operators hand while operating it. Upon one face ofthe bar 30 and near one end, a leaf spring 33 is secured with plates 35positioned at either side thereof by screws 34: which are threaded intothe bar 30. The plates 35 and spring 33 are provided with elongatedslots 36, whereby the resiliency of the spring may be adjusted to havevarious predetermined values.

The free end of the spring 33 is formed with an offset portion 38terminating in a U shaped hook 39, which forms a pocket 40 between thespring which normally rests with a predetermined pressure against thebar 30 and the end ll thereof. (See Fig. 3.) The end ll of the bar isformed with a short right angle arm l2 extending in the oppositedirection as the offset portion of the spring 33, and provided uponopposite faces thereof with slots and 4A, which form fixed jaws, thewidth of the openings therein being substantially the thickness of thesprings to be adjusted. The opposite end of the bar 30 is also formedwith a short right angle arm 47, disposed oppositely to the arm .l2 andprovided upon its outside face with a slot a8, the opposing faces ofwhich form a fixed jaw, the depth of which is substantially the width ofthe contacting portion 50, and the width of the opening therein beingsubstantially the thickness of the spring to be adjusted.

In the use of the tool, after the multicontact brush 11 has beenproperly secured to the brush rod 12, the contacting portion 50 of thespring to be gauged and adjusted is first adjusted to form asubstantially right angle bend with the contacting edge thereof lyingflat against the contacting metal strip of the commutator. Thisadjustment is made by entering the portion 50 of the spring near thepoint where it joins the longer portion thereof within the depression 18of the arm 47 as clearly shown in Figs. 1 and 2, and then twisting thebar 30 so as tobend the portion 50 either up or down until it formssubstantially a right angle bend with its end face resting flat againstthe contact strip. To adjust the portion 50 of the adjacent spring, thetool is engaged therewith from the opposite edge as clearly shown indotted outline in Fig. 2.

After the adjustment of the portion 50 of the spring, the next step isto gauge the contact pressure of the spring. This is done by enteringthe long portion of the spring to be gauged and near the upper endthereof into the U shaped hook 39 or within the pocket 40 between theend of the leaf spring 33 and the bar 30 as shown in full and dottedoutline respectively in Fig. 3. In this position it will be observedthat the leaf spring 33 rests against the bar 30. The

operator'now slowly moves the bar 30 forward, away from the spring 14being gauged, and if the contacting end of the portion 50 of the spring1e breaks contact with the contacting metal strip at simultaneously withthe disengagement of the leaf spring 33 from the bar 30 as clearly shownin Fig. 4;, it is an indication that the contact pres sure of the spring1-l is normal. If the contacting end of the portion 50 breaks contactwith the strip 27 before the leaf spring 33 breaks engagement with thebar 30, it is an indication that the pressure of the spring is belownormal, and if the re verse, that it is above normal. The adjacentspring is similarly gauged by merely moving the tool to the left andslightly rearward as viewed in F 3, with the exception that the springis entered within the pocket 40 between the end of the leaf spring 33and the bar 30 as clearly shown in dotted outline in Fig. 3. The nextadjacent spring is similarly gauged, with the exception that the tool isengaged therewith from the opposite edge thereof by entering it withinthe U shaped hook 39 of the leaf spring 33 as clearly shown in dottedoutline in Fig. 3. W' hen the contact pressure of the spring let isfound to be under or over the required pressure, the tool is positionedadjacent the upper end of the long portion thereof, which is enteredwithin either the slots 43 or 44, depending upon what spring is to beadjusted. The tool is then lowered to engage the spring near its loweror supporting end (see Figs. 2 and 3), and by twisting the bar 30 so asto bend the spring either toward or away from the contacting strips 27,the contact pressure will be increased or decreased respectively.

What is claimed is:

1. In a device for gauging the resiliency exertedby springs, a support,a member of predetermined resiliency having a portion at its free endnormally contacting therewith, and another portion adapted to engagesprings to be tested, and means for securing the member in a pluralityof adjusted positions upon the support.

2. In a device for successively gauging the contact pressure exerted byclosely spaced adjacent springs mounted in the same plane, a member ofpredetermined resiliency having a U shaped free end forming a pluralityof parallel disposed surfaces for engaging springs from the oppositeedges thereof.

3. In a device for successively gauging the contact pressure exerted byclosely spaced adjacent springs, a support, a member of predeterminedresiliency adjustably mountet. thereon, having a portion shaped t?engage springs from opposite edges there- 0 4:. In a. device forsuccessively gauging and adjusting the contact pressure exerted byclosely spaced adjacent springs, a support, and a member ofpredetermined resiliency mounted thereon, having a portion shaped toengage springs from opposite edges thereof, said support having meansformed therein for adjusting the contact pressure of the springs undertest.

5. In a device for successively gauging and adjusting the contactpressure exerted by closely spaced adjacent springs, a support havingjaws formed thereon for adjusting the contact pressure of springs undertest, a leaf spring of predetermined resiliency mounted thereon, havinga plurality of parallel disposed portions for engaging springs fromopposite edges thereof.

6. In a device for successively gauging and adjusting the contactpressure exerted by closely spaced adjacent springs of the leaf type, asupport having jaws formed at opposite ends thereof for adjusting thecontact pressure of springs under test, a leaf spring of predeterminedresiliency mounted thereon, having an offset U shaped free end normallycontacting with the support at one point to form a pocket between onearm of the U shaped end and the adjacent surface of the support, andanother within the U shaped end thereof for engaging springs fromopposite edges thereof,

7. In a device for successively gauging the contact pressure exerted byclosely spaced adjacent springs, a support, a member of predeterminedresiliency mounted thereon and normally contacting therewith at its freeend and having a portion adapted to engage springs to be tested, theresilient member having such a degree of resiliency that it disengagesthe support at the instant the spring under test disengages theassociated contact, thereby indicating that the contact pressure of thespring under test is normal.

8. In a device for successively gaugin the contact pressure exerted byclosely space adjacent springs, a support, a leaf spring ofpredetermined resiliency adjustably mounted thereon and normallycontacting therewith near its free end, and having a plurality ofparallel disposed portions at its free end for engaging springs to betested, the leaf spring having such a degree of resiliency that itdisengages the support at the instant the spring under test disengagesthe associated contact, thereby indieating that the contact pressure ofthe spring under test is normal.

In witness whereof, I hereunto subscribe my name this 21st day ofSeptember A. D.,

CHARLES BREVET EMERY.

